How to replace horn in yorkville 300k?

Hi, I’ve got a Yorkville 300k mixer amp that seems to have a bad diaphragm in the left tweeter. I hear a buzzing coming from there. So I tried to get at it to confirm but got as far as the mesh grill and tweeter faceplate and can’t seem to find an easy way to get inside to take out the driver. The cabinet looks like it’s glued wood all around.

Anyone know if there’s something I have to unscrew to open it up?

You're probably right. I don't see any other way. I noticed the tweeter faceplate seemed to be glued to the plywood with a foam like substance. I'm guessing the woofer is also glued like this, which will probably require prying? Is this glue/foam available anywhere to reseal the tweeter and woofer? Sorry if these are noob questions. First time I've taken apart PA gear built like this.
I couldn't tell from the photo, is the tweeter's square plate mounted inside or outside? It looked inside to me, but it was hard to see.

They don't glue the drivers in as a rule, but they do seal them with foam or something else to prevent air leaks around them, which can whistle. And that can get pretty sticky. There are many suitable maqterials, most from the hardware store as weatherstripping. yes, I often have to pop a driver free with a screwdriver.